<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meat name="viewpoet" content="with=device-width, initial-scale=1.0">
        <title>Document</title>
        <style>
            * {
                margin: 0;
                padding: 0;
            }

            ul {
                display: flex;
                border-bottom: 2px solid #e01222;
                padding: 0 10px;
            }

            li {
                width: 100px;
                height: 50px;
                line-height: 50px;
                list-style: none;
                text-align: center;
            }

            li a {
                display: block;
                text-decoration: none;
                font-weight: bold;
                color: #333333;
            }

            li a.active {
                background-color: #e01222;
                color: #fff;
            }
        </style>
</head>

<body>
    <div id="app">
        <ul>
            <li v-for='(item,index) in list' :key="item.id" @click="activeIndex = index">
                <a :class="{active:index === activeIndex}" href="#">{{item.name}}</a>
                <!-- <a :class='{active:true}'></a> -->
            </li>
        </ul>
    </div>
    <!-- 引入的是开发版本包 - 包含完整的注释和警告 -->
    <script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                activeIndex: 0,  //记录高亮
                list: [
                    { id: 1, name: '京东秒杀' },
                    { id: 2, name: '每日特价' },
                    { id: 3, name: '品类秒杀' }
                ]
            }
        })
    </script>

</body>

</html>